The present invention relates to a water mist cooling system having a significant advantage over prior art water mist cooling systems.
Water mist cooling systems have been in use for a number of years, and are especially used in areas having a hot, dry climate, e.g., the southwestern United States. Water mist cooling systems are also used in hot, humid areas where such systems are installed on fans to aid evaporation.
Mist cooling or flash evaporative cooling (FEC) is a rapidly growing market. There are a large number of suppliers to this industry, and ease of entry into the business is one of the reasons for said large number of suppliers. Unfortunately (for the customers/users of such systems) the prior art systems have a serious shortcoming, i.e., short duration of effective cooling followed by a requirement for maintenance and repair, as will be explained below. A typical prior art system of the type presently being offered by such suppliers is illustrated in FIG. 1, where tap water flows through an optional pre-filter (for removing suspended solids in the tap water) and thence, optionally, to a pump and a regulator R, and thence to a series of nozzles N connected serially together.
Some of the prior art systems merely operate with tap water pressure, i.e., eliminating the illustrated pump and regulator; these systems are especially unsatisfactory, since tap water pressure is typically relatively low. One problem with tap water pressure type systems is that the relatively low pressure means large droplet size. Instead of evaporating, the large droplets provide a shower effect below the nozzles. Even the systems using a pump, so as to operate at a higher water pressure, are not satisfactory as will be explained.
As indicated above, misting is used in hot, dry areas, and water quality in such arid regions is almost always very poor, i.e., the water has a very high level of total dissolved solids (TDS), usually expressed in parts per million (PPM). The nozzle orifices are very small, e.g., 0.001xe2x80x3 to 0.010xe2x80x3. Thus, when such prior art systems are used, the high mineral content of the water in the arid regions very rapidly clogs the small misting nozzles. To further explain the problem, during periods of non-use, the high mineral content water leaves a scale similar to that left in a coffee pot. The scale breaks off and becomes the sand which clogs the nozzles. Clogged nozzles have a dual negative effect. First, they do not mist, or mist improperly; and second, by not flowing, they cause excessive backpressure to the pumping system, causing premature pumping system failure. Thus, clogged nozzles disable the entire mist cooling system.
The present invention provides a mist cooling system wherein a tap water supply is connected to a pump which is adapted, when actuated, to pump the tap water from outlet means thereof at a preselected pressure. The system further comprises a plurality of misting nozzles serially connected by hollow tubing means to form a line having two ends, the first of said two ends being connected to said outlet means of said pump, whereby tap water is pumped by said pump through said hollow tubing means to said misting nozzles and thence through said nozzles as a misting spray to the atmosphere. The pump is controlled whereby tap water is pumped by said pump at a preselected pressure through said hollow tubing means to said misting nozzles and thence exiting said nozzles as tap water mist to the atmosphere to provide the cooling. Finally, and very importantly, the present invention includes a water pressure regulator at the other or second of said ends of the line of misting nozzles. The regulator is set (pressure release setting) at a preselected pressure which takes into account the water pressure in the line produced by the pumping action of the pump so that, at least intermittently, the entire line will be flushed by water exiting the line via the bypass outlet of the regulator valve. Such flushing reduces clogging of the nozzles. Prior art systems may discharge excess fluid at the beginning of a line of nozzles, but that does not flush from the line impurities or contaminates which are thereby trapped in the system.